Phosphors are used in fluorescent lamps, luminous indications, X-ray inspection systems, CRTs, vacuum ultraviolet excited light-emitting devices and so on. Known phosphors include aluminates [for example, BaMgAl10O17:Eu] and borates [for example, (Y,Gd)BO3:Eu] as red phosphors, silicates [for example, CaMgSi2O6:Eu] as blue phosphors and silicates [for example, Zn2SiO4:Mn] as green phosphors, and they are used in plasma displays (hereinafter, referred to as PDPs) and vacuum ultraviolet excited light-emitting devices such as rare gas lamps.
The vacuum ultraviolet excited light-emitting devices are light-emitting devices in which plasma is generated by electric discharge in a rare gas, and a phosphor is excited by irradiating vacuum ultraviolet rays emitted from the plasma onto the phosphor, thereby resulting in emitting visible rays from the phosphor.
The brightness of the conventional phosphors decreases when the phosphor is exposed to the plasma.